docs: def query(self, titles, pageids=None, cparams=None):
          """
          Returns MediaWiki action=query query string
          """
          query = self.QUERY.substitute(
              WIKI=self.uri,
              ENDPOINT=self.endpoint,
              TITLES=safequote(titles) or pageids)
          status = titles or pageids
  
          if pageids and not titles:
              query = query.replace('&titles=', '&pageids=')
  
          if cparams:
              query += cparams
              status += " (%s)" % cparams
  
          if self.variant:
              query += '&variant=' + self.variant
  
          self.set_status('query', status)
  
          return query